diff mbox

[v2,3/3] binfmt_misc: add F option description to documentation

Message ID 1456429136.2377.7.camel@HansenPartnership.com (mailing list archive)
State New, archived
Headers show

Commit Message

James Bottomley Feb. 25, 2016, 7:38 p.m. UTC
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 Documentation/binfmt_misc.txt | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Randy Dunlap Feb. 29, 2016, 5:32 a.m. UTC | #1
On 02/25/16 11:38, James Bottomley wrote:
> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> ---
>  Documentation/binfmt_misc.txt | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/binfmt_misc.txt b/Documentation/binfmt_misc.txt
> index 6b1de70..a22eb69 100644
> --- a/Documentation/binfmt_misc.txt
> +++ b/Documentation/binfmt_misc.txt
> @@ -66,6 +66,13 @@ Here is what the fields mean:
>              This feature should be used with care as the interpreter
>              will run with root permissions when a setuid binary owned by root
>              is run with binfmt_misc.
> +      'F' - fix binary.  The usual behaviour of binfmt_misc is to spawn the
> +      	    binary lazily when the misc format file is invoked.  However,
> +	    this doesn't work very well in the face of mount namespaces and
> +	    changeroots, so the F mode opens the binary as soon as the
> +	    emultation is installed and uses the opened image to spawn the

	    emulation

> +	    emulator, meaning it is always available once installed,
> +	    regardless of how the environment changes.
>  
>  
>  There are some restrictions:
>
diff mbox

Patch

diff --git a/Documentation/binfmt_misc.txt b/Documentation/binfmt_misc.txt
index 6b1de70..a22eb69 100644
--- a/Documentation/binfmt_misc.txt
+++ b/Documentation/binfmt_misc.txt
@@ -66,6 +66,13 @@  Here is what the fields mean:
             This feature should be used with care as the interpreter
             will run with root permissions when a setuid binary owned by root
             is run with binfmt_misc.
+      'F' - fix binary.  The usual behaviour of binfmt_misc is to spawn the
+      	    binary lazily when the misc format file is invoked.  However,
+	    this doesn't work very well in the face of mount namespaces and
+	    changeroots, so the F mode opens the binary as soon as the
+	    emultation is installed and uses the opened image to spawn the
+	    emulator, meaning it is always available once installed,
+	    regardless of how the environment changes.
 
 
 There are some restrictions: